Wiltshire Council
In the 12 months since the shocking attack, some 250 detectives have worked on the investigation, collecting more than 11,000 hours of CCTV footage and 1,700 statements from the public.
The site has been declared decontaminated after an almost year-long military clean-up operation.
Almost a year after Sergei and Yulia Skripal were poisoned, people are still told not to pick up litter.
The entire roof is to be removed.
20 teenagers in Salisbury were left needing medical treatment.